CRUSTACEANS Pasiphaeidae, is made the subject of the following note in the Fauna of Liverpool, ' This, which appears to be a rare British species, has been given to me by a Dee fisherman. All the Hoylake men know it, and say that they may, on an average, meet with one in a week. The specimen is in the Royal Institution Museum.'^ That the naturalist should prize one prawn above another because it comes more seldom into the net, is a species of idolatry or form of foolishness which the ordinary fisherman is very unwilling to encourage. Mr. A. O. Walker also records P. sivado from the ' Mouths of the Dee and Mersey, scarce.' But if every fishing boat finds on an average one every week, the scarcity for scientific purposes is rather artificial than real. From the shrimps and from one another the three prawns above named are easily distinguished. The shrimps alone have the first pair of legs sub-chelate, by which is meant that the penultimate joint or ' hand ' is not produced into an elongate process or ' thumb ' more or less parallel with the last joint or ' finger." The finger folds down on the distal margin of the hand. In Pandalus montagui the first legs are provided with minute chels. In Leander the nippers are well developed, and in Pasiphaa they attain a conspicuous length, both finger and thumb being strikingly denticulate along their confronting margins, with curved apices which cross one another when the chela is closed. This species, like the shrimps, has an insignificant rostrum, while both the other prawns are armed with a long dentate frontal horn. In general aspect all the three differ among themselves considerably, owing to the superior size of Leander serratus and the singular lateral compression of the Pasiphaa. From the family Hippolytidse Messrs. F. W. Keeble and F. W. Gamble attribute more than one species to this county. Part of their work on the colour physiology of Hippolyte varians (Leach) was done at the Piel Laboratory, and they say, ' Hippolyte varians is one of the few Crustacea which may be considered abundant in the neighbourhood of Piel. It keeps for the most part to beds of weeds below low-water mark, and hence its habits have largely to be learnt from specimens in captivity.' They found that ' fresh weed or the dead bodies of its fellows serve Hippolyte as food.' In the Barrow Channel, they say, ' Shades of brown and yellow are abun- dant, whilst green and red are sometimes common, sometimes rare. With the large Halidrys siliquosa a dark brown variety is associated ; among the fine Polyzoon {Bowerbankid) which clothes the lower parts of the Halidrys stems, a speckled variety of Hippolyte occurs : in the tide-pools of Foulney Island the green variety, and it alone, is found among the Zostera^ As a result of their experiments they say, ' We have arrived at the conclusion that there are two colour-phases in Hippolyte varians; one diurnal, the other nocturnal. The recurrence of these phases is to some extent independent of the conditions of illumination, although the colour itself may be profoundly influenced by varying the quality and intensity of the incident light, and also by other stimuli, which do not act through the eye.' Lastly they say, ' The species of Crustacea we worked with have been kindly identified by A. O. Walker, Esq. From the very limited fauna of Piel shore it may be of interest to gwQ the list, which, however, is not quite complete. Hippolyte varians (Leach), common, just below the level of ordinary spring tides. Hippolyte fascigera (Gosse), a doubtful species; almost certainly a variety of 1 Op. cit. S3- ,163
